<?php
require_once ('client/facebook.php');

$appapikey = '';
$appsecret = '';
$facebook = new Facebook($appapikey, $appsecret);
$user = $facebook->require_login();

$appcallbackurl = '';  

//catch the exception that gets thrown if the cookie has an invalid session_key in it
try
{
	if (!$facebook->api_client->users_isAppAdded())
	{
		$facebook->redirect($facebook->get_add_url());
	}
}
catch (Exception $ex)
{
	//this will clear cookies for your application and redirect them to a login prompt
	$facebook->set_user(null, null);
	$facebook->redirect($appcallbackurl);
}
